A typical fluid coupling arrangement for connecting two flanged fluid conducting tubes together includes a clamp assembly having two clamp members pivoted together at one end with a locking mechanism at the opposite ends of the clamp members to secure the opposite ends together, such that the clamp members form generally a circle around the flanges of the tubes to thereby clamp the flanges together. In use, the tubes are placed end to end such that the flanges thereof are adjacent each other with a gasket therebetween. The clamp members are then disposed around the flanges and secured together by the locking mechanism, thus clamping the flanged tubes together in a fluid tight manner.
This type of coupling is generally difficult and cumbersome to operate, requiring two hands to operate. Further, with certain designs of this coupling arrangement a problem arises when the tubes are pressurized and the locking mechanism is not completely tightened. In this situation, fluid may leak from between the joined flanges due to a gap that typically exists between the outer perimeter of the gasket and the inner surfaces of the clamp members. The pressurized fluid causes the gasket to blow out, because of the gap, thus permitting fluid to escape. This problem is of particular concern in industries in which sanitary conditions must be maintained, where if a fluid leak occurs, the system must be shut down to permit the system to be sanitized. This is both time consuming and expensive.
Other known coupling arrangements for connecting fluid conducting tubes include U.S. Pat. Nos. 5,390,963; 4,776,614; 4,366,945; and 3,655,225. However, none of these couplings is able to connect two flanged tubes end to end with a gasket between the flanges of the tubes. This means that portions of the coupling arrangement are wetted by the fluid flowing through the tubes, thus precluding the use of these couplers in situations where sanitary conditions must be maintained.
Therefore a need exists for an improved coupling that is able to couple two flanged fluid conducting tubes in an end to end relationship with a gasket between the flanges, such that none of the surfaces of the coupling are wetted by the fluid within the tubes. The coupling should be quick and easy to use, permit one-handed operation, and further prevent seal blow out.